A high voltage installation refers to a collection of electrical equipment permanently interconnected, capable of receiving electricity from the infrastructure of an electricity entity or a generating source at voltages exceeding 1000V AC RMS or 1500V ripple-free DC.

This encompasses electrical equipment linked to protection and earthing systems, extending to low voltage cables and switchgear associated with high voltage installations. However, high voltage installations exclude:

1. Electric discharge illumination systems
2. X-ray equipment
3. High-frequency equipment
4. High voltage wiring and electrical equipment enclosed within self-contained electrical equipment and supplied at low voltage, with precautions taken to prevent contact with high voltage conductors.

As per Section 221 of the Electrical Safety Regulation 2013 (the ES Regulation), it is mandated that an auditor conducts an inspection of high voltage electrical installations before their connection or reconnection to a power source under the following conditions:

1. The high voltage electrical installation is being connected for the first time.
2. Electrical installation work has been carried out on the high voltage electrical installation.

This pre-commissioning inspection ensures compliance with relevant standards for the installation, associated electrical equipment, and protective equipment.